The head of Transparency International wrote an op-ed in The Guardian and attempted to strike a positive tone by pointing to the success of Hong Kong:

Corruption can be tackled, but the reforms must run deep...

The creation of a strong anti-corruption body proved a turning point in Hong Kong in the 1970s, helping it emerge from the control of organised crime to its present reputation for integrity – it's now ranked 14th in Transparency International's Corruption Perceptions Index. It has prosecuted more than 12,000 public officials.

Greece, sitting 80 places further down that ranking, needs to follow that example and allow no impunity for corruption.

Here is the infographic showing the countries perceived as most corrupt in the OECD, starting with the least corrupt.